1. Field of the Invention
The present invention relates to a photonic crystal film used for an optical path divider for optical communications and WDM transmission/reception module, and so on, a method of manufacturing a photonic crystal, a mask, a method of manufacturing a mask, an optical device and a method of manufacturing an optical device.
2. Description of the Related Art
First, using a mask with a single cyclic structure allows a photonic crystal of holes to be easily realized on the polymer thin film. Furthermore, the same applies to a case where a mask having a single cyclic structure is used even when a material other than polymer is used as the photonic crystal material.
First, a method of manufacturing a photonic crystal having a single cyclic structure, which is a conventional example of a photonic crystal using a mold having a single cyclic structure will be shown in FIG. 10 (see Japanese Patent Laid-Open No. 2000-258650), the entire disclosure of which is incorporated herein by reference in its entirety.
A substrate 101 is pressed using a mold 102 to have a convexo-concave pattern and this substrate is subjected to anode oxidization in oxalic acid, whereby the substrate is transformed into a metal oxide thin film 105 having a cyclic nano-hole structure 104.
Thus, a single cyclic structure can be easily transferred to an object by pressing a mold having a single cyclic structure.
By the way, a method of manufacturing a photonic crystal having a single cyclic structure, which is this inventor's own invention described in Japanese patent Application No. 2001-105447 for a photonic crystal using a mask having a single cyclic structure will be shown in FIG. 9(A) and FIG. 9(B). The entire disclosure of Japanese Patent Application No.2001-105447 is incorporated herein by reference in its entirety. Since the inventor's own Japanese Patent Application No.2001-105447 was not published at the Priority Date(Dec. 13, 2001) of this application, the invention described in Japanese Patent Application No.2001-105447 is not prior art.
When a slab waveguide made up of a polymer thin film 91 formed on a glass substrate 90 is prepared (see FIG. 9(A), a mask 92 having the same single cyclic structure as a conventional photonic crystal structure is placed on the polymer thin film 91 of the slab waveguide, and then an ion beam 95 is injected, trackings 93 are formed by ions 94 injected at positions of windows (through hole 96 ) of the mask on the polymer thin film 91 (see FIG. 9(B)). These trackings 93 are changed to holes through alkali treatment and a cyclic structure of holes having the same single cyclic structure as that of the mask on the polymer thin film 91 is formed.
Thus, using a mask with a single cyclic structure allows a photonic crystal of holes to be easily realized on the polymer thin film. Furthermore, the same applies to a case where a mask having a single cyclic structure is used even when a material other than polymer is used as the photonic crystal material.